Nintendo and The Pokemon Company released an official app on the iOS App Store.
The Pokedex for iOS app is now available on the official App Store on iOS platforms. The reference app bears a striking resemblance to the previously released Pokedex 3D Pro for the 3DS, though each has unique features. All 647 Pokemon (and their alternate forms) are available in the application via in-app purchases. It is a universal app so a single purchase works on iPhones, iPod Touches, and iPads. It requires iOS 6.0.
Users of the app are able to use extensive search options to discover Pokemon. Once viewing a Pokemon, they can see a unique animation, hear their cry, see their stats, and understand their abilities. The app is also capable of storing custom notes for each monster.
The app can be downloaded for $1.99. The initial download features entries for Pokemon #494-647 (The Unova Region). Pokemon from Kanto (#1-151), Johto (#152-251), Hoenn (#252-386), and Sinnoh (#387-493) can be added via in-app purchases. Each region's set costs $5.99. Therefore, to outfit the app with every Pokemon, the final cost of Pokedex for iOS would be $25.95.
Note: There are many nonofficial Pokedex apps available on the App Store. At the time of this writing a simple search for 'Pokedex' will not reveal the official app from The Pokemon Company. It is recommended that you search for 'Pokedex for iOS' as a phrase and make sure you are downloading the one provided by The Pokemon Company.